Along with the rapid development of display technology, touch panel has been widely used in our daily lives. Currently, the touch panel may include, on the basis of its constitution and structure, an add-on mode touch panel, an on-cell touch panel and an in-cell touch panel. For the add-on mode touch panel, it is produced independently of a liquid crystal display (LCD) and then adhered thereto, so it has such drawbacks as high manufacturing cost, low light transmittance and a thick module. For the in-cell touch panel, its touch electrode is built in the LCD to reduce the thickness of the entire module and significantly reduce the manufacturing cost of the touch panel, so this kind of touch panel is favored by many manufacturers.
Recently, an existing capacitive in-cell touch panel is obtained by forming two layers of crisscross, transparent conductive electrodes, usually bar-like indium tin oxide (ITO) electrodes, on a surface of a thin film transistor (TFT) array substrate as touch driving electrodes and touch sensing electrodes, respectively, and an inductive capacitance is formed at a junction of two ITO electrodes. Such a touch panel operates as follows. When a touch scanning signal is applied to the touch driving electrode, a touch sensing signal coupled by the touch sensing electrode through the inductive capacitance is detected, and at this time, an electric field of a human body acts on the inductive capacitance if the touch panel is touched by the human body, so as to change a value of the inductive capacitance, thereby to change the touch sensing signal coupled by the touch sensing electrode. Then, a touch position may be determined in accordance with the change of the touch sensing signal.
For the design of the above-mentioned capacitive in-cell touch panel, it is required to add a new membrane on the existing TFT array substrate, resulting in an increase in a thickness of the touch panel. In addition, an additional process step is required when manufacturing the TFT array substrate, so the production cost will increase and the production efficiency will be lowered.